1. Field of the Invention
The present invention relates to a three-dimensional image display apparatus.
2. Description of the Related Art
As one of three-dimensional display methods to enable a three-dimensional display used in amusement, Internet shopping, carrying terminal, medical care, virtual reality, an advertisement signboard, and so on, there is a stereoscope system that displays plane images for right and left eyes on a display screen, to watch the right eye plane image with the right eye and the left eye plane image with the left eye, using polarized light.
The stereoscope system requires polarized glasses for a viewer, for example, in order to see the right eye plane image with the right eye and the left eye plane image with the left eye. This stereoscope system can make an image seen three-dimensionally. However since it does not play back three-dimensional image really, even if the viewer changes position to look at the image, the image does not change. In other words, even if the viewer changes the position to look at the side and top face of the image, he or she cannot see the side and top face of the image. Therefore, the stereoscope system has a problem in reality.
Further, in the stereoscope system, an accommodation position exists on a display screen, a spatial displacement occurs between the accommodation position and the convergence location at which a gaze object exists. More specifically, mismatch occurs between accommodation and convergence distance, and a playback space makes a viewer feel sense of incongruity, to be easy to give fatigue to the viewer.
As a three-dimensional display method for solving these problems is known a method referred to as an integral photography method or a light beam reproduction method using a great number of parallax images (Jpn. pat. Appln. KOKAI Publication 10-239785, and Jpn. pat. Appln. KOKAI Publication No. 2001-56450). The method records a three-dimensional image by means of some manners and plays back it as a three-dimensional image. The integral photography method or light beam reproduction method is not established in semantics of a vocabulary as a three-dimensional display method precisely, but based on approximately the same principle. An integral photography using a pinhole array plate, for example, is well known from a long time ago. This can be referred to as the light beam reproduction method. An integral photography method as a concept including a light beam playback method will be described hereinafter.
A three-dimensional display apparatus using the integral photography method comprises a display device such as a liquid crystal display panel and an array plate having pinholes arrayed two-dimensionally, and plays back a natural three-dimensional image by a simple optical system. The integral photography method can form a natural three-dimensional image with a simple configuration. Since the integral photography method reproduces a three-dimensional image really, polarized glasses are not required, and the observed three-dimensional image changes in correspondence with the angle at which a viewer watches the three-dimensional image. Thus, the three-dimensional image represents a feeling of more reality. However, it is difficult that the integral photography method reproduces a high definition three-dimensional image. Since the integral photography method plays back a three-dimensional image using light beams emitted from element image via a pinhole, three-dimensional image must be displayed using many element images that are arranged two-dimensionally.
Light beams of a desired color and luminance are emitted from a pixel (referred to as triplet) having subpixels of R (red), G (green) and B (blue) through a pinhole. Increase of the number of light beams emitted from the pinhole increases the three-dimensional effect. However, since the number of pixels of a display panel is limited, the number of pinholes also is limited. In other words, since the number of pinholes is equal to the number of plane pixels usable as the three-dimensional display, the three-dimensional image is missed in fineness.
Further, the integral photography method or light beam reproduction method needs data compression due to a great amount of data. The definition of the reproduced three-dimensional image deteriorates significantly due to this data compression.
It is an object of the present invention to provide a three-dimensional display apparatus that can display a high definition three-dimensional image.